Pectoral Sandpiper

Calidris melanotos

Order: Charadriiformes

Family: Scolopacidae

Pectoral Sandpiper with worm. via: A.J. Hand

Description

This medium sized sandpiper is probably one of the most abundant in Alaska.  They have a medium sized bill that is yellowish at the base and grades to a dark brown at the tip.  They have yellowish-greenish legs.  The chest is densely streaked down to the sharp border with the starkly white belly.  The back is a reddish-brown and they have a slightly whitish eye-stripe.  In flight, their wings are dark without a prominent stripe (unlike the Dunlin).  They also have a broad black center on the rump and upper tail that is pretty distinguishable when in flight.  Pectoral Sandpipers are sexually dimorphic and the male can be 25-30% larger than the female.

Diet

Like the Dunlin and other sandipers, the Pectoral Sandpiper feeds primarily on freshwater, marine and terrestrial invertebrates.  They will also occasionally feed on seeds and algae.   

Range/Habitat

Distribution map of Pectoral Sandpiper. via: Audubon Birds

Breeds in coastal tundra in Alaska and Canada.  Migrates to wintering grounds in southern and south-central South America and is typically found in wet meadows, mudflats, and shores of ponds and lakes.  Those at the extremes of the range (breeding in Siberia) will migrate a total of 30,000 km, which is comparable to the Arctic Tern. 

Breeding/Nesting

Pectoral Sandpipers nest on ground in tundra grasses.  They have a polygynous mating system, which is atypical of other sandpipers in the calidris genus (more like the Buff-breasted Sandpiper Tryngites subruficollis).  An interesting fact, males have an inflatable throat sac that they contract and expand during display flights.  They make sounds, like a series of hollow hoots with it.  The display flights are also a territorial defensive behavior.  They will also puff out their feathers on the upper breast and follow the female around while also raising tail vertically and "hooting" at her.  He will also swat from side to side and then wave his wings with the neck stretched. 

Breeding male erects feathers on breast in display.
via: Birds of North America

From Audubon Birds: 

To ensure an adequate supply for the young, male Pectoral Sandpipers depart for the south before the eggs hatch, so they don't compete for food with the mothers and their chicks. Then the adult females leave, too, and in the last few weeks the young have the tundra to themselves.

However, that could just be a function of the polygynous mating system, since the males will not incubate or care for the young.

The females are solely responsible for building the nests, which is another atypical attribute to the genus (remember how male Dunlins made the scrapes that the females choose from).  They will lay four eggs that are pyriform in shape and are an olive to cream buff color.  They are also spotted dark brown, purplish or gray and are more densely spotted at the widest end, often forming a large dark blotch.